1. Technical Field
The present invention relates to a projector.
2. Related Art
There is known a projector that modulates, according to image information, a light beam emitted from a light source and magnifies and projects the light beam on a screen using a projection optical device.
In such a projector, the light beam is tilt-projected upward with the projector fixed in a low position, tilt-projected downward with the projector fixed in a high position, and, besides the projection in the vertical direction, tilt-projected in the horizontal direction. Therefore, there is known a projector including a projection position adjusting device (a lens shift mechanism) that moves, with respect to an optical system such as an optical modulation device, a projection optical device in a direction orthogonal to a direction in which a light beam is irradiated (a projecting direction) (see, for example JP-A-2004-245956, FIGS. 2 to 4).
In the projection position adjusting device disclosed in JP-A-2004-245956, a projection lens unit (a projection optical device) is fixed to a lens holder and moved in the vertical direction and the horizontal direction together with the lens holder by two driving mechanism units.
As the driving mechanism units, worms disposed to be orthogonal to each other are adopted. A rotating shaft to which a pair of pinions are fastened is rotated to move the lens holder engaged with the pair of pinions by rotating the worms.
In the projection position adjusting device disclosed in JP-A-2004-245956, the pair of worms are disposed to be orthogonal to each other. Therefore, for example, when dials operated by a user are provided at one ends of the pair of worms, respectively, it is difficult to expose the respective dials from the same end face (e.g., the top) of an armor housing configuring the projector.
In order to expose the respective dials from the same end face of the armor housing, as described in JP-A-2004-245956, a rotating shaft of the dials (knob sections) and a rotating shaft of the worms are disposed to be orthogonal to each other and the dials and the worms are connected by a pair of spiral gears. The rotating force of the dials is converted into the rotating force of the worms by the pair of spiral gears. In such a configuration, it is necessary to provide a transmission converting mechanism such as the pair of spiral gears. Therefore, simplification of the structure cannot be realized.